Long-wavelength opticalnetworking brings singlemodefiber into data centersHyperscale data centers are the most prominent,but not the only data center facilities deployingsinglemode fiber-optic cabling systems.

BY PATRICK MCLAUGHLIN

A prevailing truth about optical networking within data centers is that deploying long-wavelength optics and singlemode fiber-optic cabling is more
costly than deploying short-wavelength
optics and multimode fiber-optic cabling. However, over the past few years,
the price of long-wave optics has fallen,
bringing them close to parity with
short-wave optics.

The world’s largest data centers,
commonly referred to as hyperscales,
have been pioneers in going singlemode. Jim Hayes, president of The Fiber
Optic Association, explained that hyperscale facilities “are following the Open
Compute Project open-source developments, have mostly upgraded to singlemode fiber, are already experimenting

Open Compute Project

On the topic of the Open ComputerProject (OCP), Anthony Haupt, datacenter solutions architect withCommScope, explained, “The OpenComputer Project’s stated mission is todesign and enable the delivery of themost efficient server, storage, and datacenter hardware design.”The initiative officially was launchedin 2011 by Facebook—which had beentrying to design the world’s most-ef-ficient data center since 2009—alongwith Intel, Rackspace, Goldman Sachsand Andy Bechtolsheim. The OCP ex-plains that these five founding mem-bers “hoped to create a movement in thehardware space that would bring aboutthe same kind of creativity and collabo-ration we see in open source software.”CommScope’s Haupt explained thatout of the OCP have come “a number ofwhitebox designs to meet the needs ofend users. The most important take-away is that OCP changed the norm.In the past, the norm was that OEMswould push standards to users. Userswould either embrace them or waitfor the next standard to arrive. Now,end-users are demanding standards andproducts to meet their needs. It’s turnedthe paradigm on its head.

“Whether or not Open Compute dic-tates or influences media type is an im-portant question that gets asked fre-quently,” Haupt continued. “OpenCompute does not necessarily dic-tate media type. But it has lent a voiceto large end users [and in doing so] ex-posed a lot of voids, which brought tech-nologies to market. In part, this hascontributed to unprecedented growthin cloud computing over the past fiveyears—and with that, increases in trans-For example, he pointed out, fiveyears ago 40-Gbit/sec was being talkedabout. Last year, 100-Gbit/sec was im-plemented in real-life networks. EchoingHayes of the FOA, Haupt added, “400Gcan’t come fast enough” for some hy-perscale data centers. “Beyond 400G weare seeing a variety of speeds pop up in

Headwinds and tailwinds

With large data centers eagerly looking
at speeds of 200 or 400 Gbits/sec, they
look closely at the practicality of implementing those speeds over short-wave/
multimode versus long-wave/singlemode constructions. Haupt dissected
these options, providing analysis of the
headwinds and tailwinds for each media
type in these environments.

“If you look at the IEEE standard

802.3bs [400-Gbit/sec], there is one protocol for multimode—400GBase-SR16,”